Weber Hydroelectric Project FERC Project No Preliminary Study Plan Water Quality

Transcription

1 Weber Hydroelectric Project FERC Project No Preliminary Study Plan Water Quality Prepared by: PacifiCorp Hydro Resources 1407 West North Temple, Room 110 Salt Lake City, UT For Public Review

2 TABLE OF CONTENTS 1.0 INTRODUCTION PROJECT AREA BACKGROUND Existing Data Water Quality Upstream and Downstream of the Dam Nexus to the Project PROPOSED WATER QUALITY STUDY Monitoring Locations Water Quality Parameters Biological Assessments Quality Assurance, Quality Control Reporting Schedule and Cost REFERENCES List of Tables Table 1. Summary of Use Designations for the Weber River-3 Assessment Unit... 4 Table 2. Monthly Summary of Water Quality Data for Field Parameters* for the Weber River-3 Assessment Unit, Table 3. Summary of Monthly Water Quality Data for Nutrient, Sediment, and Hardness Parameters for the Weber River-3 Assessment... 7 Table 4. Summary of Average Annual Water Quality for the Weber River-3 Assessment Unit, Table 5. Paired Water Quality Parameters and Average Percentage of Difference for Upstream and Downstream Sampling Locations Table 6. Monitored Parameters and Associated Utah Water Quality Standards Table 7. Proposed Tasks and Associated Potential Costs List of Figures Figure 1. Weber Hydro Relicensing Project Location Figure 2. Map of Existing Water Quality Data Locations Figure 3. Maximum temperature values by season from 1995 to 2005 compared to the UDEQ temperature standard of 20 C (red dashed line) for Class 3A waters. The average maximum value from 1995 to 2005 is also shown (green dashed line) for reference Figure 4. Minimum DO values by season from 1995 to 2005 compared to the UDEQ DO Figure 5. Maximum and average specific conductance by season from 1995 to Figure 6. Matched pair values for specific conductance upstream and downstream of the dam from 2003 to Figure 7. Matched pair values for turbidity upstream and downstream of the dam from 2003 to Figure 8. Water Quality Sampling Locations Figure 9. RIVPAC Assessment Locations in the Weber River - 3 AU Page i

3 1.0 INTRODUCTION PacifiCorp, a subsidiary of Berkshire Hathaway Energy, plans to file a new application for relicense of a major project, the Weber Hydroelectric Project (Project), Federal Energy Regulatory Commission (FERC or Commission) Project No. 1744, on the Weber River in Weber, Morgan, and Davis counties in Utah. The current license will expire on May 31, The Project has a generation capacity of 3.85 megawatts (MW) and is located partially on federal lands managed by the Wasatch-Cache National Forest, and partially on lands owned by the Union Pacific Railroad Company. PacifiCorp filed a Notice of Intent to File Application for New License (NOI) and a Pre-Application Document (PAD) to initiate the Federal Energy Regulatory Commission s (FERC) Alternative Licensing Process (ALP) for the Project on May 29, During preparation of the PAD, PacifiCorp conducted a desktop-level assessment to evaluate existing water quality data for the Weber River and to inform analysis of potential Project impacts on water quality. One of the more significant findings from the assessment is that recent comprehensive water quality data (within the last 10 years) for the portion of the Weber River in question are lacking. This lack of data prohibits a rigorous assessment of potential project impacts to this resource from Project operations without obtaining additional water quality sampling data. The importance of such data is evident given that the Weber River is a highly valued and heavily used resource in Utah, with several stakeholder groups deeply vested for a variety of reasons that include agriculture, municipal water supply, recreation, and fishing. Generally speaking, water quality in the Weber River watershed is moderately degraded with approximately 56% of assessed water bodies meeting beneficial uses as defined and classified in Utah Administrative Code R and R (Weber River Partnership 2014). Common causes for impairments include low dissolved oxygen (DO), high temperatures, high nutrient levels, sedimentation, and habitat degradation. This water quality study plan aims to achieve three two goals: 1) to gain a better understanding of current water quality in the Project area; and 2) to determine the effect of Project operation on water quality and address the specific 401 water quality certification standards to ensure that the federally permitted or licensed activities are conducted in a manner that will compliesy with applicable discharge and water quality requirements in order to maintain the chemical, physical, and biological integrity of waters of the United States within the State. and 3) determne any minimum instream flows to meet goal #2. Achievement of the study plan goals will identify whether there is a need to develop project-specific mitigation measures for water quality in the Project area. The guiding principles behind the water quality study plan and monitoring strategy will be the beneficial uses and associated Utah water quality standards assigned by the Utah Division of Water Quality to the portion of the Weber River within the Project Area. Page 1

4 2.0 PROJECT AREA For the purposes of this document, the FERC Project Boundary (or Project Boundary) is defined as all lands and waters within the existing FERC Project Boundary for the Weber Hydroelectric Project No. 1744, as denoted on the project s Exhibit G. The Project Area is the area that contains all project features (encompassing the FERC Project Boundary defined above) and that extends out for the purposes of characterization and analysis from the farthest edge of the Project Boundary across the river to the far riverbank (including the river regardless of which side of the river the project features are found), as shown in Figure 1. The existing Project consists of: (1) a 27-foot-high, 79-foot-long concrete diversion dam, having two radial gates approximately 29 feet wide, and a 35-foot-wide intake structure, for a total width of 114 feet, on the Weber River; (2) a 9,107-foot-long, 5-foot to 6.3-foot diameter steel pipeline partially encased in concrete beginning at the intake and terminating at the powerhouse on the Weber River; (3) a 3-foot by 18-foot non-operative fish passage structure (used however to pass the minimum flow through the calibrated slide gate opening); (4) a powerhouse containing a generating unit with a rated capacity of 3,850 kilowatt (kw) operating under a head of 185 feet producing a 30-year average annual energy output of 16,932 megawatt-hours (MWh); (5) a discharging pipe returning turbine flows into the Weber River at the powerhouse; and, (6) a 77-foot-long, 46-kilovolt (kv) transmission line which connects to the Weber substation. Page 2

5 Figure 1. Weber Hydro Relicensing Project Location. Page 3

6 3.0 BACKGROUND 3.1 Existing Data A water quality analysis as it relates to the Weber Dam and its operation was conducted using existing water quality data from the Weber River-3 Assessment Unit (AU) (UT ). According to the 2014 Integrated Report (Utah Department of Environmental Quality [UDEQ] 2014), AUs are delineated by the Utah Division of Water Quality based on similarity in physical, chemical, and biological conditions of a waterbody. The Weber River-3 AU extends from the confluence with the Ogden River upstream to the confluence with Cottonwood Creek. It is approximately 19.5 miles long and encompasses the entirety of the Weber Project Area. Beneficial uses for this portion of the river are identified as Class 2B, 3A, and 4. The description for each Class is provided in Table 1. The 2014 Integrated Report lists the Weber River-3 AU as not supporting because it does not meet beneficial use 3A due to a biological impairment (UDEQ 2014). While this AU is listed as impaired and will require a total maximum daily load (TMDL) study, the current TMDL priority is low (UDEQ 2014), and has not been scheduled. Table 1. Summary of Use Designations for the Weber River-3 Assessment Unit Class 2B 3A Designated Beneficial Use Protected for infrequent primary contact recreation where there is a high low likelihood of ingestion of water or a high low degree of bodily contact with water. Protected for cold-water species of game fish and other cold-water aquatic life, including the necessary aquatic organisms in their food chain 4 Protected for agricultural uses including irrigation of crops and stock watering Source: Utah Administrative Code R317-2 Water quality data for the Weber River-3 AU were obtained from the U.S. Environmental Protection Agency STORET Data Warehouse. Database queries covered two STORET stations, one of which is located approximately 1 river mile upstream of the Project Area (Station ID ) and one that is located approximately 12.6 miles downstream of the Project Area (Station ID ) (Figure 2). Data from 1995 to 2006 were used, and the specific parameters analyzed included ph, specific conductance, turbidity, DO, temperature, alkalinity, phosphate, hardness, and total suspended solids (TSS). Monthly and annual water quality parameters are summarized in Tables 2, 3, and 4. Page 4

7 i _::: County Boundary 05 -= =Kilometers Miles !I Comains prlv/ittged Information.Do tjoi re/9an. lmegttryfrom NAIP: 2014 Figure 2. Map of Existing Water Quality Data Locations. Preliminary Study Plan - Water Quality Page 5

8 Table 2. Monthly Summary of Water Quality Data for Field Parameters* for the Weber River-3 Assessment Unit, January February March April May June July August September October November December Mean ph Average Maximum Minimum Specific conductance (umho/cm) Average Maximum Minimum Turbidity (NTU) Average Maximum Minimum DO (mg/l) Average Maximum Minimum Temperature, water ( o C) Average Maximum Minimum Notes: umho/cm = micromhos per centimeter; NTU = nephelometric turbidity units; mg/l = milligrams per liter; ºC = degrees Celsius *Utah State water quality standard limits listed in Table 6 of Section 4.2, this document. Page 6

9 Table 3. Summary of Monthly Water Quality Data for Nutrient, Sediment, and Hardness Parameters for the Weber River-3 Assessment Unit, January February March April May June July August September October November December Mean Alkalinity, carbonate as CaCO3 (mg/l) Average Maximum Minimum Hardness, Ca + Mg (mg/l) Average Maximum Minimum Phosphate-phosphorus as P (mg/l) Average Maximum Minimum Solids, total suspended (mg/l) Average Maximum Minimum Page 7

10 Table 4. Summary of Average Annual Water Quality for the Weber River-3 Assessment Unit, ph Specific conductance (umho/cm) Turbidity (NTU) DO (mg/l) Temperature, water ( o C) Alkalinity, carbonate as CaCO3 (mg/l) Hardness, Ca + Mg (mg/l) Phosphate-phosphorus as P (mg/l) Solids, total suspended (mg/l) Dash = Data not available. Page 8

11 Seasonal water temperatures from 1995 to 2006 ranged from lows of 0 2 o C during the winter (December through February) to highs of o C during the summer months (June through August). Variation in average annual temperature is relatively small with the greatest difference occurring from 1998 to 1999 (see Table 4). From 1995 to 2005, maximum temperatures occurred during the summer months with the highest temperature recorded during the summer of 2003 at 22.2 o C (Figure 3). The UDEQ cold-water fishery temperature standard states that greater than 10% of samples must exceed 20 C in order for the waterbody to be listed as impaired. It should be noted that while this data set does include temperatures that surpass 20 C, fewer than 10% of the samples exceeded 20 C. In addition to denoting the 20 C standard, Figure 3 also shows the average maximum temperature from 1995 to 2005, further identifying temperature conditions in the Weber River-3 AU and illustrating that as it relates to fisheries, temperature is not a water quality issue for the time period covered by this data set. Figure 3. Maximum temperature values by season from 1995 to 2005 compared to the UDEQ temperature standard of 20 C (red dashed line) for Class 3A waters. The average maximum value from 1995 to 2005 is also shown (green dashed line) for reference. Average alkalinity (ability of the water to neutralize a strong acid) ranged from 124 mg/l to 219 mg/l over the analyzed period with lower values occurring in late spring and higher values occurring in winter. Similarly, total hardness (Ca++ and Mg++) ranged from 152 mg/l to 267 mg/l with lower values occurring in late spring and higher values occurring in winter. Data indicate that water hardness and alkalinity in the Weber River-3 AU is on the high end; however, for this area of Utah, these values are reasonable. On a seasonal basis, the highest concentrations are found during low-flow periods driven by groundwater recharge, with low concentrations occurring during snowmelt and spring runoff. The ph along this portion of the Weber River remains relatively stable, with average monthly values ranging from 8.0 in April to 8.4 in July. Page 9

12 High concentrations of DO ( mg/l or greater) are important for the health and viability of fish and other aquatic life in the Weber River. Low DO concentrations (less than 4.0 mg/l) can cause an increase in stress to fish species and lower resistance to environmental stress and disease, and can ultimately result in mortality (at levels less than 2.0 mg/l). Low DO in water bodies can be related to a number of factors that include decomposition of algae and other organic matter and subsequent depletion of DO. From 1995 to 2006, DO ranged from 6.3 mg/l to 14.1 mg/l in the Weber River-3 AU with an overall average of 10.4 mg/l. The minimum DO water quality standard of 4.0 mg/l as a 1-day minimum was not exceeded during this time period (Figure 4). It should be noted that several other DO state water quality criteria apply to the designated uses assigned to Weber River-3 AU; however, the existing data set used for this analysis precluded the application of these standards. Figure 4. Minimum DO values by season from 1995 to 2005 compared to the UDEQ DO standard of 4 C 4.0 mg/l as a 1-day minimum (red dashed line) for Class 3A waters. Seasonal average specific conductivity ranged from 168 mg/l to 733 mg/l with an average value of 517 mg/l from 1995 to Seasonally, higher values were observed during the low flows of the winter months (Figure 5), possibly due to groundwater sourcing of flow or surface runoff containing dissolved solids associated with deicing roads. Turbidity ranged from 1 NTU to 110 NTU with an average value of 10 NTU, and TSS ranged from 0 mg/l to 273 mg/l with an average value of 22 mg/l. These two parameters (turbidity and TSS) are particularly important for understanding macroinvertebrate habitat because an increase in these parameters can indicate that pores of the streambed are becoming clogged with sediments, causing a reduction of habitat diversity and surface area available for microbial and macroinvertebrate growth and, subsequently, for habitat availability and surface protection for eggs and juvenile fish to become limited. Page 10

13 Figure 5. Maximum and average specific conductance by season from 1995 to Water Quality Upstream and Downstream of the Dam Paired data points from 2003 and 2004 were identified from the two water quality monitoring stations and compared to gain insight into differences in water quality upstream and downstream of the Project Area. Table 5 summarizes the number of data pairs available and the average difference and percentage change from upstream to downstream in water quality for all paired water quality samples for these stations. Trends were graphically explored for specific conductance and turbidity due to the magnitude of difference in matched pairs. Both specific conductance and turbidity are higher at the downstream sampling station versus the upstream sampling station (Figures 6 and 7). These differences are likely due to the fact that the upstream and downstream sampling stations are far enough apart (13.6 miles total) that other factors may be influencing these parameters, including that the downstream site is likely being affected by the urban corridor it traverses. Additional data will be acquired so that the degree to which the Project is affecting water quality can be identified. While historical data are useful for characterizing the evolution of water quality in the watershed, the addition of more recently collected data in closer proximity to the Project Area will be helpful for determining current trends and informing additional resource studies and courses of action during the relicensing process. Page 11

14 Table 5. Paired Water Quality Parameters and Average Percentage of Difference for Upstream and Downstream Sampling Locations Parameter Number of Data Pairs Average Upstream Average Downstream Average Difference Percentage Change ph % Specific conductance (umho/cm) % Turbidity (NTU) % DO (mg/l) % Temperature, water ( o C) % Alkalinity, carbonate as CaCO3 (mg/l) % Hardness, Ca + Mg (mg/l) % 3.3 Nexus to the Project Water quality may be affected by all types of diversion dams, however the Weber Hydroelectric Project is a run-of-the-river facility with a very small forebay and associated short retention time. PacifiCorp does not flush the Project forebay to reduce sediment build- up, although limited dredging may occur periodically on an as-needed basis. Historically, when dredging does occur, any dredged materials are removed and disposed of at an off-site location. There are no other Project operations that are known to affect water quality parameters such as temperature, ph, and DO. Page 12

15 Figure 6. Matched pair values for specific conductance upstream and downstream of the dam from 2003 to Figure 7. Matched pair values for turbidity upstream and downstream of the dam from 2003 to Page 13

16 4.0 PROPOSED WATER QUALITY STUDY 4.1 Monitoring Locations PacifiCorp will evaluate the current water quality conditions in the Project Area to determine if beneficial uses and associated Utah state water quality standards are being met and address the specific 401 water quality certification standards to ensure that the federally permitted or licensed activities arewill be conducted in a manner that will compliesy with applicable discharge and water quality requirements in order to maintain the chemical, physical, and biological integrity of waters of the United States within the State. and to determne any minimum instream flows to meet goal #2 to determine the effects of the project on water quality parameter PacifiCorp has selected three locations to monitor water quality: 1) upstream of the Weber Diversion Dam in the eastern portion of the Project Area, 2) downstream of the Project dam in the bypass reach, and 3) the lower end of the bypass reach just downstream of the point where bypass water mixes with powerhouse discharge, and upstream of the point it enters the Weber-Davis Canal (Figure 8). All sondes will be placed in the river at locations most likely to be representative of the entire stream channel. Where possible, bridges or other infrastructure will be used to secure sondes in the middle of the river. At the third downstream-most site, the sonde will be placed as close to the middle of the river as possible and anchored by chaining it to boulders. 4.2 Water Quality Parameters As stated previously, this portion of the Weber River is a part of the Weber River-3 AU, which extends from the confluence with the Ogden River upstream to the confluence with Cottonwood Creek. It is approximately 19.5 miles long, and beneficial uses for this portion of the river are identified as 2B, 3A, and 4. Utah state water quality standards associated with these beneficial uses, as well as the potential for impacts from Project operations, drove the selection of parameters to be monitored for this study plan. Water quality parameters to be monitored include temperature, ph, DO, and turbidity. In addition to monitoring the four parameters with state water quality standards, PacifiCorp also proposes to monitor TSS and specific conductance because these two parameters can lend additional insight into water quality issues. The water quality parameters and associated Utah state water quality standards are listed in Table 6. Page 14

17 Figure 8. Water Quality Sampling Locations Page 14

18 Table 6. Monitored Parameters and Associated Utah Water Quality Standards Parameter Utah Water Quality Standard Temperature (max/change) 20 C /2 C ph DO 1 (30-day average) (7-day average) (1-day minimum) Turbidity (increase) TSS Specific conductance 6.5 mg/l 9.5/5.0 mg/l 8.0/4.0 mg/l 10 NTU No water quality standard No water quality standard 1 First number in column details when early life stages are present; second number details when all other life stages are present. To capture current water quality conditions and evaluate potential impacts to water quality from Project operations, a YSI 6920 V2-2 Multiparameter Water Quality Sonde will be deployed at each of the three sampling locations by in February January The sondes will be used to record temperature, ph, DO, turbidity, and specific conductance data on an hourly basis. The sondes will remain at the three locations for approximately 1 year to capture all hydrologic periods, including baseflow, spring runoff, and storm flows. Grab samples for laboratory analysis of TSS will be taken once a month and during any planned Project operations that may affect TSS Biological Assessments The 2014 Integrated Report lists the Weber River-3 AU as not supporting because it did not meet beneficial use 3A due to a biological impairment (UDEQ 2014; note however that the 2014 report did not include the most recent 2013 data due to EPA review time laglaboratory turn-around time). UDWQ determines biological impairments through the use of biological assessments that are conducted using the River Invertebrate Prediction and Classification System (RIVPACS) model which classifies sites based on macroinvertebrate fauna. RIVPACS generates quantitative model outputs that are assigned narrative descriptions that are then used to support narrative water quality criteria (UDEQ 2014). The Weber River-3 AU was first listed as biologically impaired in 2008 (which was finalized in the 2014 Integrated Report and which used data collected prior to 2008), however, athe most recent biological assessment conducted by UDWQ in 2013 indicates that beneficial uses are currently being met. Specifically, the 2013 assessment examined four sites within the Weber River-3 AU, one of which is located in the project area. Of the four sites sampled within the Weber River-3 AU, two were found to be in GOOD condition, one in FAIR condition, and one in POOR condition, based on the RIVPACS model output (Figure 9). According to the UDWQ assessment methodology for listing biological impairments, that more than one site per reach Page 16

19 must be determined to be in POOR condition for the reach to be listed as not-supporting (in this case, Page 17

20 Figure 9. RIVPAC Assessment Locations in the Weber River - 3 AU. Page 18

21 only one1 of the four4 sites was in POOR condition), therefore, the most current data for Weber River Reach-3 AU indicates that beneficial use 3A is currently s for macroinvertebrates are being met. Per discussion with UDWQ staff, Tthese findings will likely result in a recommendation for delisting of the Weber River-3 AU. Additionally, the site located within the project area is in GOOD condition and the site upstream of the project area is in POOR condition indicating that project operations are unlikely to be affecting biological integrity. Due to the potential recommendation for delisting of the Weber River-3 AU and the site- specific results of the 2013 biological assessment, additional macroinvertebrate sampling and habitat characterization wereare not included as a part of this study plan. 4.3 Quality Assurance, Quality Control QA/QC is an integral part of any water quality study plan and is best described as a set of activities and procedures designed to assure the reliability and accuracy of data and the attainment of quality standards. QA/QC is addressed by establishing both field and laboratory checks that result in qualitative and quantitative measurements of data quality. QA/QC procedures carried out for this study plan include calibrating and servicing water quality sondes on a monthly basis. After sonde deployment, monthly service trips will be conducted (at the same time as TSS sampling) to ensure that sondes are recording data properly. All sondes will be calibrated according to manufacturer s instructions, and batteries will be replaced during monthly checks. Prior to sampling for TSS, all sampling containers will be acquired from the contract laboratory. Once collected, samples will be kept on ice and delivered to American West Analytical Laboratory in Salt Lake City within the appropriate holding time and under the standard chain of custody protocols. 4.4 Reporting Results of the water quality study will be presented in a technical report that will include the following components: Detailed descriptions of the procedures and methods used to collect and analyze water quality data Presentation of the water quality results in both tabular and graphical format Statistical analysis of the water quality results by hydrologic period Discussion and summary of findings with a comparison to State water quality standards both up and down gradient of the Project area. Identification of project impacts on water quality including a discussion of any impacts from proposed project facility modifications Project upgrades (if any) Recommendations for mitigation of project impacts on water quality (if any) 4.5 Schedule and Cost Water quality monitoring equipment is expected to be installed at the three sampling locations Page 19

22 identified in section 4.1 by early February Data will be gathered for approximately 1 year to capture all hydrologic periods and any Project operations that may impact water quality. Following the field effort, all water quality data will be analyzed and presented in a draft report (section 4.4). Stakeholder and agency comments will be addressed within a 2-week period following the 30-day review period, and the report then will be finalized and submitted to FERC. The estimated cost for each component of this study is presented in Table 7. Table 7. Proposed Tasks and Associated Potential Costs Task Cost Water quality sondes deployment and use $7,391 Water quality sampling $11,251 Laboratory analysis $776 Reporting $5,533 Total $24, REFERENCES Utah Department of Environmental Quality (UDEQ) Integrated Report. Available at: ent/curr entiroct.htm. Accessed July 22, Utah Administrative Code R Standards of Quality for Waters of the State. Accessed: August 26, Available at: Page 20